Western Road Trip

[eganders]

I am planning a road trip in mid-May that will take in Las Vegas, Salt Lake City, Yellowstone, Mt. Rushmore, Rocky Mountain National Park (Estes Park) and the Grand Canyon. The trip is about 3300 miles and is about 18 days. Six days are just driving locally (less than 100 miles). Most of the driving days are 150 to 300 miles. There are two days that are almost 400 miles. One of these 400 mile days is from Rapid City, SD to Estes Park, CO which concerns me somewhat.
Although none of the driving days have overwhelming miles in themselves, I am concerned about the total of 3300 miles in 18 days. I would like some thoughts on this,

Also, we are looking for interesting places to stay. I am OK on Las Vegas. I am planning on staying at the following locations:
Ruby's Inn (Bryce Canyon)
Antler Inn (Grand Tetons)
Old Faithful Inn (Yellowstone)
Country Inns & Suites (Mount Rushmore) (any more interesting suggestions?)
Pine Haven (Estes Park )
Cascade Resort & Spa (Vail) (any more interesting suggestions?)
Ramada (Arches National Park/Moab)
Hampton Inn (Monument Valley area)
Bright Angel Lodge (Grand Canyon)

I would like any alternative suggestions.
Any other thoughts about this area, how long to stay at each location, any special rental vehicle and any other suggestion would be appreciated.